We have developed a facile and rapid synthesis of a highly fluorescent nanocrystal (NC) library, based on ultrasonic and combinatorial chemistry. Among a total of 66 tZAIS ((Zn_xAg_yIn_z)S₂) NCs, many NCs are highly fluorescent upon UV irradiation, and are categorized into blue, green, yellow, orange, and red by their distinct emission wavelength ranges. The tZAIS NCs not only have long fluorescence lifetimes, but also show comparable or even higher brightness than QDs without photoblinking in single NC analysis. Their unique photophysical properties together with less-toxic nature can permit the tZAIS system to be practically utilized in various bioimaging fields, especially single nanoparticle-based imaging and tracking.